Due to widespread use of smart speakers and other voice-activated devices, there are increased opportunities to use voice in order, for example, to launch an application or search for information without performing a particular procedure, such as pressing a button, before utterance. A voice is usually uttered to a smart speaker or other voice-activated device without pressing, for example, a button to indicate the start of voice input. Therefore, when an unintended voice is uttered, the voice-activated device may perform an operation not intended by a user.
There is a technology for determining whether or not the user is uttering a voice to a microphone (hereinafter referred to as the mic) in order to suppress the voice-activated device from performing an operation not intended by the user. This technology uses, for example, image data acquired by capturing an image of the user. In this instance, however, a camera needs to be installed to acquire such image data. This results in an increased cost and in a complex system. In addition, many users are reluctant to be photographed for such image data acquisition.
Examples of the related art include Japanese Laid-open Patent Publication No. 10-243494, Japanese Laid-open Patent Publication No. 2016-181789, and Japanese Patent No. 5387459.